This relates generally to electronic devices, and more particularly, to electronic devices with displays.
Electronic devices often include displays. For example, cellular telephones and computers may have displays for presenting information to a user.
Liquid crystal displays contain a layer of liquid crystal material. Pixels in a liquid crystal display contain thin-film transistors and electrodes for applying electric fields to the liquid crystal material. The strength of the electric field in a pixel controls the polarization state of the liquid crystal material and thereby adjusts the brightness of the pixel.
Substrate layers such as color filter layers and thin-film transistor layers are used in liquid crystal displays. A thin-film transistor layer contains an array of the thin-film transistors and associated pixel electrodes that are used in controlling electric fields in the liquid crystal layer. A color filter layer contains an array of color filter elements such as red, blue, and green elements. The color filter layer provides the display with the ability to display color images.
In an assembled display, components are coupled to one or more of the substrate layers in the display. For example, in a display in which the thin-film transistor layer forms the outermost display layer of the display, the thin-film transistor layer may have a ledge region that extends past the edge of the color filter layer. Components such as a flexible printed circuit and display driver integrated circuit may be mounted to contacts in the ledge region, Alignment tolerances may be tight when mounting these components. As a result, it may be desirable to form mating alignment marks on the thin-film transistor layer and on the components being mounted to the thin-film transistor layer. If care is not taken, however, the alignment marks may be visible from the exterior of the display.
It would therefore be desirable to be able to provide improved alignment structures for displays such as liquid crystal displays.